View Single Post
  #57   Report Post  
Old January 5th 04, 08:00 AM
Pete KE9OA
 
Posts: n/a
Default

It might be a good thing, if only I could get one of them to work properly.
The quasi-sync detector has been the best sounding one so far, but it is no
better than the TDA1572's balanced detector.
The 4046/SA602 detector still needs some work.................I think that
Phase Detector 2 is unsuitable for this purpose. I need to use Phase
Detector 1, which shifts the VCO by 90 degrees. This could work, if I can
come up with a suitable phase shift network.
I just completed the intial design of the AD607 based sync detector, and
boy, does this one have problems! When I am tuned to center channel, the
system howls, but if I detune to either LSB or USB, everything is ok. This
circuit is based on Mike Murphys application note from Analog Devices. It
just may work out, with some fine tuning. This has been the best iteration
so far. Analog Devices has eliminated the AGC detector in the latest
versions of the AD607, whereas Mr. Murphy's design is based on one of the
older versions that does have this detector. I do have some samples of the
older version, so I will throw that on the board tomorrow, and see how it
works out.
Those sync detectors have been the hardest part of this radio design!
Compared to my current iterations, the Icom R75 sync detector is a gem. This
gives you an idea of just how bad my sync detectors are! I'll get them
running.........they are only a collection of parts!

Pete

starman wrote in message
...
Pete KE9OA wrote:
snipped

On the subject of the R75, I know, the sync detector isn't the best in

the
world


Pete,

Have you thought about incorporating one of your sync' detector designs
to the R75? It might prove to be the ultimate sync' mod for it.


-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----